1. Field of the Invention
The present disclosure relates to an integrated hybrid heat exchanger for a hybrid vehicle. More particularly, it relates to an integrated hybrid heat exchanger with a multi-sectional structure, in which an electrical component cooling system and an internal combustion engine cooling system are integrated into a single cooling system and a radiator for preventing thermal shock and providing thermal resistance is provided to improve cooling efficiency and durability.
2. Description of Related Art
In general, a hybrid vehicle is a vehicle that is equipped with an internal combustion engine and a motor such that the vehicle is driven by one or both of the engine and the motor.
The hybrid vehicle is driven by the motor during initial driving or during cruise driving and is driven by the internal combustion engine during uphill driving or during battery discharge, thus improving fuel efficiency.
Here, since electrical components including the motor generate heat during operation, it is necessary to provide a cooling system that prevents an increase in the temperature of the components in order to maintain the input and output characteristics of the components at an optimum state.
Especially, in the case of a battery, it is necessary to maintain an optimum temperature in order to maintain the overall charge-discharge efficiency at its best.
Accordingly, the heat generated during the charge and discharge of the battery is cooled to the optimum temperature using the cooling system.
For example, when the hybrid vehicle is driven by the motor, heat is generated by a phase shift of current (AC to DC) in an inverter, and heat is also generated during operation of the motor and an electric generator. In order to cool these electrical components, the hybrid vehicle includes an electrical component cooling system in which cooling water is circulated through an electric pump→the inverter→an inverter reservoir tank→a radiator during operation of the motor.
Accordingly, a hybrid cooling system is operated by two cooling systems including the electrical component cooling system and an internal combustion engine cooling system.
In this hybrid cooling system, the internal pressures of an integrated radiator, in which individual radiators are hydraulically isolated from fluid communication with each other, may be different from each other according to the operation of the internal combustion engine and the electric motor, the flow rate of a water pump, and the temperature of coolant. In this case, the dynamic pressures may be different from each other even if the total pressures are the same.
Recently, an integrated cooling system, in which the electrical component cooling system and the internal combustion engine cooling system are integrated into a single cooling system so as to provide an improvement in cooling efficiency, an advantage of layout design, a reduction in the number of components, and a reduction in manufacturing cost, is proposed.
For example, Japanese Patent Publication No. 1998-259721 and U.S. Pat. No. 6,124,644 disclose cooling systems, in which an existing internal combustion engine radiator is divided into a radiator for an internal combustion engine and a radiator for electrical components.
However, in the case of the cooling system disclosed in Japanese Patent Publication No. 1998-259721 and the cooling system disclosed in U.S. Pat. No. 6,124,644, the radiator for the internal combustion engine having a higher operating temperature (about 112° C.) and the radiator for the electrical components having a lower operating temperature (about 80° C.) are in direct contact with each other, and thereby heat is continuously conducted to diaphragm and core portions. As a result, the temperature of the radiator for the electrical components is increased, which deteriorates the efficiency of electrical components reduces the output power during operation of the electrical components.
Moreover, the operation of the internal combustion engine is stopped during cold start at sub-zero temperatures (for example, −20° C.) and only the electrical system is operated. In this case, if coolant at a temperature (for example, 60° C.), heated by the operation of the electrical components is suddenly supplied to the radiator for the electrical components, the contractile force at the lower temperature side and the expansive force at the higher temperature side are simultaneously generated at the diaphragm portion, the core portion, and a bonding portion between the core and header, thus causing thermal shock.
If such a situation continues for a long time, it may cause leakage due to fatigue at the direct contact portions.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.